580MPa级热轧高扩孔钢的组织与性能

MICROSTRUCTURES AND PROPERTIES OF 580 MPa GRADE HOT-ROLLED STEELS WITH HIGH HOLE-EXPANDING RADIO

采用Nb、V、Ti微合金化,通过TMCP工艺试验,研究了Nb、V、Ti微合金对低碳钢显微组织、力学及成形性能的影响,并分析了影响扩孔性能的因素。研究结果表明,适当加入微合金Nb、Ti,能够大幅度提高试验钢的强度,同时延伸率、硬化指数、扩孔性能良好;热轧高扩钢中的贝氏体能够起到阻挡裂纹扩展的作用,导致裂纹扩展转向,铁素体-贝氏体组织有利于钢板扩孔性能的提高。

The effects of microalloy Nb, V, Ti on microstructures, mechanical properties and forming properties of low carbon steels through TMCP tests ,and the influeing factors of hole-expanding properties were investigated. The results indicated that the addition of microalloy elements Nb and Ti could enhance tensile properties intensively and elongation, hardenability value as well as flange formability. The bainite could hinder the propagation of crack, inducing the direction turning away. The microstructure of ferrite and bainite was beneficial to increase the flange formability of steels.